Les systèmes d'information entre formel et informel.

There is no doubt that formalising information systems is of great value to a company. This enables, among others, business processes, rules, services and objects models to be standardized, structured, capitalized and reused. A formal information system involves a structured organization, clearly defined roles and responsibilities and therefore a rational management. The Formal is thus more structuring, segmenting and may be associated with referential and standards. However, generalizing a formalisation approach to all information system perspectives or all levels of granularity can inversely be fatal to the smooth running of the business, its management, and operation. The aim of this paper is to explore information systems formal-informal continuum, to discover and understand its characteristics, patterns, anti-patterns, and the forces participating to its equilibrium. (English) [ABSTRACT FROM AUTHOR]